Minimally Invasive Method For Coronary Bypass And Other Treatments

ABSTRACT

Treatment methods and devices are provided for percutaneously accessing a patient&#39;s thoracic region via a controlled opening in the aorta, so that cardiac procedures, such as a coronary bypass procedure, can be performed in a minimally invasive manner. Advantageously, it may be possible to perform the procedure without placing the patient on cardiopulmonary bypass. The method may include percutaneously delivering at least one catheter into an aorta of a heart, forming a controlled opening in the aorta and pericardium via the at least one catheter to access a thoracic region within the patient&#39;s chest, and performing at least one coronary bypass graft procedure through the controlled opening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/992,860, filed Dec. 6, 2007. The application is incorporated hereinby reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates generally to minimally invasive methodsfor performing cardiac medical and/or surgical procedures, and moreparticularly to percutaneous methods for performing a coronary arterybypass graft (CABG) procedure on a patient in need thereof.

Coronary artery disease remains a leading cause of morbidity andmortality in Western societies. A number of approaches have beendeveloped for treating coronary artery disease. It is often sufficientto treat the symptoms with pharmaceuticals and lifestyle modification tolessen the underlying causes of the disease. In more severe cases, thecoronary stenoses may be treated endovascularly using techniques such asballoon angioplasty, atherectomy, laser ablation, stenting,thrombectomy, and the like.

In still more severe cases where pharmaceutical treatment and/orconventional endovascular approaches have failed or are likely to fail,it may be necessary to perform a coronary artery bypass graft procedureusing open surgical techniques. Such techniques require that a patient'ssternum be opened, the chest spread apart to provide access to theheart, and the heart stopped. While very effective in many cases, theuse of open surgery to perform coronary artery bypass grafting is highlytraumatic to the patient. The procedure requires immediate postoperativecare in an intensive care unit, hospitalization for five to ten days,and a recovery period as long as six to eight weeks.

Alternative techniques have been devised to perform coronary bypasssurgical procedures thorascopically. Examples of such procedures aredisclosed in U.S. Pat. No. 7,131,447 and No. 7,028,692 to Sterman etal., and in U.S. Pat. No. 5,888,247 to Benetii. Although such methodsare believed to decrease morbidity, mortality, cost, and recovery timewhen compared to conventional open surgical coronary bypass procedures,they still require stopping the patient's heart and placing the patienton cardiopulmonary bypass.

It would be desirable to provide a better method for performing acoronary bypass procedure that is less invasive than open surgical orthorascopic techniques. It would also be desirable to provide aninterventional procedure that does not require use of cardiopulmonarybypass.

SUMMARY OF THE INVENTION

Methods and devices are provided for performing a medical procedure on apatient's heart. In one aspect, the method includes (i) percutaneouslydelivering at least one catheter into an aorta of the heart; (ii)forming a hemostatic connection between the at least one catheter and aninner wall of the aorta; (iii) creating an aperture through the aortaand pericardium, said aperture being bounded by the hemostaticconnection, thereby forming a controlled opening to access a thoracicregion of the patient's chest through the at least one catheter; and(iv) performing a cardiac procedure through the controlled opening. Inone embodiment, a method is provided for performing a coronary bypassprocedure on a patient's heart comprising: (i) percutaneously insertingan end of at least one catheter into the ascending aorta; (ii) forming acontrolled opening in a wall of the aorta via a lumen of the insertedend of the at least one catheter, wherein the controlled opening isoutwardly directed from the wall of the aorta into a thoracic regionwithin the patient's chest; and (iii) performing at least one coronarybypass graft procedure through the controlled opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a catheter disposed in a partial sectional view of ahuman heart and its associated proximate vascular system.

FIG. 2 illustrates a view of the heart of FIG. 1 with a hemostaticconnection between the catheter and aorta according to one embodiment.

FIG. 3A illustrates a catheter according to one embodiment.

FIG. 3B illustrates a hemostatic connection and controlled opening inthe aortic wall of the heart shown in FIG. 2.

FIGS. 4A and 4B illustrate a flange in a non-expanded and expandedposition in and extending from a catheter according to one embodiment.

FIG. 5 illustrates a device and method for forming a hemostaticconnection between the catheter and aorta according to one embodiment.

FIG. 6 illustrates a device and method for forming a hemostaticconnection between the catheter and aorta according to anotherembodiment.

FIG. 7 illustrates a view of the heart of FIG. 1 undergoing a coronarybypass graft procedure according to one embodiment.

FIG. 8 illustrates a view of the heart of FIG. 5 undergoing a coronarybypass graft procedure according to one embodiment.

FIGS. 9A and 9B illustrate a lock and key stent for use in a coronarybypass graft procedure before and after, respectively according to oneembodiment.

FIGS. 10A and 10B illustrate a magnetically linked catheter both beforeand after passage of a loop glide wire from a first catheter to a secondcatheter.

FIG. 11 illustrates a stent for the formation of an end-to-sideanastomosis in a coronary bypass graft procedure according to oneembodiment.

DESCRIPTION OF THE INVENTION

Methods and devices are provided for performing a variety of cardiacmedical procedures on a patient in a minimally invasive manner. As usedherein, the term “patient” refers primarily to a human adult or child,but also may include other suitable mammalian animals, for example in apre-clinical trial or in veterinary care.

The interventional medical procedure preferably is conductedpercutaneously, which involves accessing the heart via a blood vesseland a catheter introduced therein using a needle puncture. A wire may beintroduced through the lumen of a needle and catheters can be deliveredover the wire into the blood vessel and guided to the heart. In apreferred embodiment, the procedures may be conducted without placingthe patient on cardiopulmonary bypass.

In one aspect, a method is provided for percutaneously performing acardiac procedure on a patient's heart. In one embodiment, the methodincludes the steps of percutaneously delivering at least one catheterinto the aorta above the beating heart; forming a hemostatic connectionbetween the at least one catheter and an inner wall of the aorta orother vascular structure; creating an aperture through the ascendingthoracic aorta or other vascular structure acting as an inflow conduit,said aperture being bounded by the hemostatic connection, therebyforming a controlled opening to access a thoracic region of thepatient's chest through the at least one catheter; and performing acardiac procedure through the controlled opening. In one embodiment, thecardiac procedure is a coronary bypass graft procedure. In otherembodiments, the cardiac procedure may be a valve repair, a valvereplacement, or a thermal and mechanical cardiac ablation procedure tocorrect arrhythmias. Other procedures known in the art may also beadapted to be performed through the controlled opening.

In a preferred embodiment, the procedure is conducted using computedtomography (CT) guidance. In another preferred embodiment, the at leastone catheter comprises a Hansen Device™. These guidance tools are knownin the art for use with conventional cardiac interventions.

In one embodiment, the coronary bypass graft procedure includes thesteps of detaching a left internal mammary artery from a patient's innerthoracic wall; occluding blood flow in the left internal mammary artery;transecting a distal end of the left internal mammary artery; forming ananastomosis between the distal end of the left internal mammary arteryand a coronary artery targeted for bypass; closing the controlledopening in the aorta and pericardium; and withdrawing the at least onecatheter from the aorta.

The percutaneous coronary bypass graft procedure may be conducted asfollows. The patient undergoing the procedure may be prepared in aconventional manner for cardiac catheterization with both groinsprepared to permit access to the femoral arteries and veins and with thearms prepared to permit access to the radial or brachial arteries andveins. The patient may be sedated for the procedure using anyappropriate means, including general anesthesia. Once anesthetized, thepatient may be intubated with a double-lumen endobronchial tube, forexample, which allows for the selective ventilation or deflation of theright and left lungs. The procedure generally should be conducted undersystemic anticoagulation, such as with either heparin or bivalirudin,and in the presence of an effective antiplatelet therapy, such asaspirin and/or a thienopyrridine drug, like Clopidogrel, or otherantiplatelet agents.

After the patient has been prepared for the procedure, appropriateincisions are made and a catheter 110 is guided toward the heart 10 fromthe descending aorta 12 through the aortic arch 14 into the ascendingaorta 16 (FIG. 1). The procedure generally may be conducted usingfluoroscopic guidance or CT guidance to obtain the desiredvisualization. Other visualization techniques well known in the art,such as MRI, ultrasound, stereotaxis, also may be used.

Access from the left and right femoral arteries may be achieved in theusual fashion and a guide may be advanced to the ostium of the leftcoronary or the right coronary as is typically performed withangioplasty. Through this guide, a guidewire may be advanced across ananatomic stenosis in the right or left coronary system usingconventional techniques. Another catheter 110 then may be advanced usingthe contralateral femoral access.

In one embodiment, the catheter 110 is used to form a hemostaticconnection 112 with the inner aortic wall 18 in an anterolateral, orotherwise preferred, projection. Alternatively, the hemostaticconnection may be made with the inner wall of any other suitable largevascular structure. The term “hemostatic connection” as used hereinmeans a connection that substantially prevents the flow of blood orother fluids at the interface of the device and inner vascular wall(i.e., the lumen-aortic interface or catheter-aortic interface) (FIG.2). In one embodiment, the catheter 110 includes a flange 114 that ispart of the catheter itself (FIG. 3A). The flange 114 may expand uponremoval of a sleeve 115 that keeps the flange in a non-expanded formuntil the distal end of the catheter 110 is in the desired positionwithin the aorta, for example (FIGS. 4A and 4B). Those skilled in theart will appreciate that the flange may assume any suitable shape,non-limiting examples of which include a rectangular, circular, orelliptical form.

The hemostatic connection between the catheter and the inner aortic wallmay be made using any suitable technique, including suction adherence,removable suture adherence, or magnetic pull from a source outside thebody on the chest wall. For example, in one embodiment, the hemostaticconnection 112 may be created by forming sutures 116 through thecatheter wall 110 to the inner aortic wall 18, which may be tightenedduring the procedure as needed and removed after the procedure has beencompleted. The hemostatic connection 112 also may be created byinflating a non-occluding balloon 117 within the aorta 16 (FIG. 5). Thenon-occluding balloon should be inflated in such a way that it providesa sufficient amount of pressure against the flange 114, thereby forminga hemostatic connection between the flange and the inner aortic wall 18.Such non-occluding balloons are known to those in the art, non-limitingexamples of which are disclosed in U.S. Patent Publication No.2007/0021818 to De Gregorio and U.S. Patent Publication No. 2004/0102732to Naghani et al. In one embodiment, the hemostatic connection 112 maybe created by extending one or more counter-supports 119 within theaorta 16 opposite the flange 114 (FIG. 6). The one or morecounter-supports should provide a sufficient amount of pressure tosecure the flange 114 against the inner aortic wall 18 and form ahemostatic connection 112.

After the hemostatic connection 112 between the catheter 110 and inneraortic wall 18 has been established, a controlled wall opening 118 iscreated through the aortic wall into the thorax (not shown) using anysuitable technique or device for forming the penetration. Non-limitingexamples of such techniques may include use of a trocar through thecatheter or use of a laser to create the controlled opening. In oneembodiment, the aorto-thoracic controlled opening may be maintained byan anchoring device delivered through the catheter, such as aself-expanding or balloon expandable fixator. This anchoring device mayremain or be removed upon aorto-coronary conduit placement. Thecontrolled opening provides an access point for a joystick-drivenblunt-tipped catheter, which may be manipulated under CT or MR guidance.Desirably, the catheter may be manipulated 360 degrees. Non-limitingexamples of such catheters include the CT-guided Hansen Device™ (HansenMedical, Mountain View, Calif.) or the MR-guided Stereotaxis MagneticNavigation System™ (Stereotaxis Inc., St. Louis, Mo.).

With the left lung selectively deflated, the joystick driven catheterthen may be used to dissect within the thorax to the pericardium. Oncethe pericardium may be visualized directly, access to the pericardiummay be achieved using a mechanical puncture or laser opening. Aguidewire may then be passed into the pericardium, thereby allowing aballoon occluding device to be advanced over the guidewire such thateither side of the balloon would allow the center of the balloon (e.g.,a dogbone shape) to forcibly tamponade the hole in the pericardium.After removing the wire, the pericardium then may be insufflated withcarbon dioxide via the balloon to provide space in which to work in thepericardium. Alternatively, the pericardium may be simply incised andopened for direct access to the cardiac anatomy.

Once access to the thorax has been accomplished with the left lungselectively deflated, the left internal mammary artery 20 may be takendown from the patient's inner thoracic wall percutaneously by a HansenDevice™ or other suitable device 120 which is advanced through thecatheter 110 (FIG. 7). Those skilled in the art will appreciate thataccess and manipulation of the left internal mammary artery may beachieved from a variety of different positions, non-limiting examples ofsuch positions include the radial, brachial, or axillary positions,depending upon the selected access sheath and device size. In oneembodiment, the left internal mammary artery is accessed by firstselectively deflating the left lung through the endotracheal tube andmaintaining ventilatory support through the right lung. The blood flowin the internal mammary artery 20 typically is stopped before take-downof the artery by introducing a separate catheter 122 through the leftradial artery and subclavian artery 22 into the internal mammary arteryand inflating a balloon 124 at the distal tip of the artery to occludeblood flow. In another embodiment, the blood flow in the left internalmammary artery is stopped using a proximal flow-occluding device. Afterocclusion of the blood flow within the left internal mammary artery 20,a laser tipped catheter 120 may be advanced through the aorto-thoraciccatheter 110 via the controlled opening 118, and used to cut and sealthe side branches of the left internal mammary artery 20, to dissect theleft internal mammary artery from the thoracic wall, and to transect thedistal tip of the artery. This process may involve simultaneousmanipulation of the left radial-to-left internal mammary artery catheter122, and the aorto-thoracic catheter 110 together to avoid trauma to theleft internal mammary artery 20 as it is being taken down from the innerthoracic wall. Suitable laser tipped catheters are known in the art, ormay fashioned to achieve this end (e.g., holmium lasers). Other commonlyused interventional cardiology or surgical devices may also be employedto this end.

After harvesting and preparing the left internal mammary artery 20 foranastomosis, the target site of the coronary artery to be bypassed isidentified. Typically, the diseased coronary artery which is the subjectof the bypass is the left anterior descending (LAD) artery 24 (FIG. 8);however, the methods provided herein also are suitable for bypassingother arteries, including the right coronary artery, the obtuse marginalartery, the ramus intermedius artery, and the posterior descendingartery.

After the take-down and transection of the left internal mammary artery20, the left internal mammary artery may be manipulated and repositionedtoward the opening of the pericardium (not shown) toward the surface ofthe LAD 24 on the top of the heart (not shown). In one embodiment, apair of magnetic tipped catheters is used to align the left internalmammary artery and LAD. A non-limiting example of such a catheter is theMagneCath™ (Ample Medical, Foster City, Calif.). In one embodiment, afirst MagneCath™ 126 is disposed in the LAD 24 (the endovascularMagneCath™) and a second MagneCath™ 122 is disposed in the left internalmammary artery 20 (the epivascular MagneCath™). The first and secondMagneCath™ then are used to align the left internal mammary artery andLAD (FIGS. 9A and 9B).

The MagneCath™ provides two complimentary shaped permanent magnets132,134 on the distal tip of the catheter 122,126 which link together(FIGS. 10A and 10B, illustrated in Circulation 113:2329-2334, 2330(2006)). Such a device allows an exact linkage between the firstMagneCath™ in the LAD distal to the significant coronary lesion and thesecond MagneCath™ in the left internal mammary artery at the epicardialcoronary distal to the lesion. The MagneCath™ 126 is a hypotube with aguidewire lumen 136 and magnet 134 at the distal tip thatcomplimentarily attaches to the interlocking magnet 132 of a secondMagneCath™ 122. The attachment of the two MagneCath™ allows for theforceable puncturing from one hypotube through the MagneCath™ 126 intothe second MagneCath™ 122. Once passed through the complimentaryMagneCath™, the guidewire 136 acts as a tether over which one candeliver devices, balloons, or in this case attach one vascular structureto another.

The MagneCath™ tips on either side of the selected artery wall ofinterest (for example, the left internal mammary artery or LAD) may bemanipulated such that they link magnetically. After the catheters aremated, a crossing guidewire 136 may be advanced from the endovascularMagneCath™ 126 into the epivascular MagneCath™ 122, linking the twodevices. This guidewire 136 may then be passed from the artery into theaorto-thoracic catheter 110 and externalized as a continuous rightcommon femoral artery-to-left common femoral artery loop or right commonfemoral artery-to-left radial artery loop to remove the MagneCath™. Overthis guidewire, a proximal occlusion balloon may be used to interruptblood flow within the selected coronary artery, while manipulation inthe epicardial space is performed.

In one embodiment, a locking vascular connector is implanted on thedistal tip of the left internal mammary artery 20 via a thoracotomy inthe anterior chest wall after the take-down of the left internal mammaryartery 20 and before the movement of the left internal mammary arteryinto position (FIGS. 9A and 9B). Alternatively, a stent 130 may beplaced in the LAD 24 to allow for use of an occlusion balloon catheterin the LAD, thereby accommodating use of an end-to-side anatastomosisbetween the left internal mammary artery and LAD (FIG. 11).

In one embodiment, the tip of the left internal mammary artery isaffixed to the LAD with a stent-like self-expanding nitinol vascularconnector, which allows for anastomosis to the coronary. The vascularconnector may comprise a singular device or multiple separate butcomplimentary or cooperative devices 127, 128 (e.g., a lock and key)disposed in the left internal mammary artery 20 and in the LAD 24 (FIGS.9A and 9B). The vascular connector 127 may be applied to the tip of theleft internal mammary artery 20 using direct force applied from thelumen outwardly or by suture to the left internal mammary artery throughthe patient's chest using a thoracotomy or through the aortothoraciccatheter or the radial catheter, while the vascular connector 128 may beattached to the LAD using direct expansive force. In a particularembodiment, the vascular connector 128 may be deployed by removal of asheath closure mechanism, similar to currently known or commerciallyavailable self-expanding stents. The vascular connector may furthercomprise a drug coating, similar to currently available drug elutingstents.

Other techniques known to those skilled in the art for joining theinternal mammary artery and the LAD include suturing, laser welding,microstapling, using a bioadhesive (e.g., BioGlue™) or a combinationthereof.

Following completion of the coronary anastomosis, the balloon occludingcatheter of the left internal mammary artery may be deflated andremoved, allowing blood to flow through the left internal mammary arteryinto the LAD. The catheter and Hansen Device™ is withdrawn from thethorax back through the catheter lumen-aortic interface, the aortic wallclosed (sealed), and the catheters withdrawn. The groin and radialpenetrations finally may be repaired as necessary.

It also is contemplated herein that a similar approach may be taken withthe right internal mammary artery or using harvested saphenous veins.For example, in an alternative embodiment, a saphenous vein may beharvested from any suitable location. In one alternative embodiment, anarterial graft is harvested from the gastroepipolic artery, the gastricartery, the radial artery, the femoral artery, the splenic artery, orthe like. Two vascular connectors may be applied to each end of the veinor arterial conduit to allow the vein or artery to be pulled forcibly oradvanced using the MagneCath™-delivered guidewire. A flexible-tippedguidewire may be passed through the coronary catheter down the vessel,out the coronary artery through the MagneCath™ into the lumen of thepericardial balloon, and then out the catheter through the aorta to thefemoral artery. The vein then may be advanced over the guidewire throughthe aortothoracic catheter into the thorax, down the wire through thepericardium, and attached to the coronary artery. A coronary arteriotomymay be necessary to advance a vein with a vascular connector over thetip. Once anastomosed to the coronary at the distal tip of the vein, theproximal aspect of the vein may be anastomosed to the thoracic aorta. Aself-expanding nitinol vascular connector at either end of the veinoptionally may be expanded. Such a procedure would provide analternative method for coronary revascularization, providing a conduitfor flow from the thoracic aorta down to the coronary artery.

Thus, the procedures described herein provide an approach for utilizingpercutaneous and aorto-thoracic means of facilitating anastomosis ofbypass conduits, the left or right internal mammary artery, or saphenousvein bypass grafts, achieving procedures which otherwise would requireopen chest coronary artery bypass grafting around significant stenosesin the native coronary anatomy. It is believed that such procedures mayresult in decreased morbidity, mortality, cost, and recovery time whencompared to conventional surgical coronary bypass procedures.

Publications cited herein and the materials for which they are cited arespecifically incorporated herein by reference. Modifications andvariations of the methods and devices described herein will be obviousto those skilled in the art from the foregoing detailed description.Such modifications and variations are intended to come within the scopeof the appended claims.

1. A method for performing a coronary bypass procedure on a patient'sheart comprising: percutaneously inserting an end of at least onecatheter into an aorta of a heart; forming a controlled opening in theaorta and pericardium via a lumen of the inserted end of the at leastone catheter, wherein the controlled opening is directly outwardly fromthe aorta into a thoracic region within the patient's chest; andperforming at least one coronary bypass graft procedure through thecontrolled opening.
 2. The method of claim 1, wherein the step offorming a controlled opening comprises forming a hemostatic connectionbetween the inserted end of the at least one catheter and an inner wallof the aorta and then creating an aperture through the wall of the aortaand pericardium, said aperture being bounded by the hemostaticconnection.
 3. The method of claim 1, wherein the at least one coronarybypass graft procedure comprises preparing a graft artery for bypass andforming an anastomosis between the graft artery for bypass and one ofthe patient's coronary arteries targeted for bypass.
 4. The method ofclaim 3, wherein the graft artery for bypass comprises a left internalmammary artery.
 5. The method of claim 3, wherein the coronary arterytargeted for bypass comprises a left anterior descending artery.
 6. Themethod of claim 4, wherein the graft artery for bypass is prepared by aprocess that comprises: detaching the left internal mammary artery froma patient's inner thoracic wall, occluding blood flow in the leftinternal mammary, and transecting a distal end of the left internalmammary artery.
 7. The method of claim 6, wherein the process forpreparing the graft artery for bypass further comprises delivering asecond catheter into the left internal mammary from a radial artery. 8.The method of claim 1, wherein at least one of the steps is conductedusing computed tomography (CT) guidance.
 9. The method of claim 1,wherein the at least one catheter comprises a Hansen Device.
 10. Amethod for performing a medical procedure on a patient's heartcomprising: percutaneously delivering at least one catheter into anaorta of a heart; forming a hemostatic connection between the at leastone catheter and an inner wall of the aorta; creating an aperturethrough the aorta and pericardium, said aperture being bounded by thehemostatic connection, thereby forming a controlled opening to access athoracic region of the patient's chest through the at least onecatheter; and performing a cardiac procedure through the controlledopening.
 11. The method of claim 10, wherein the medical procedurecomprises a coronary bypass graft procedure.
 12. The method of claim 11,wherein the coronary bypass graft procedure comprises: detaching a leftinternal mammary artery from a patient's inner thoracic wall; occludingblood flow in the left internal mammary artery; transecting a distal endof the left internal mammary artery; forming an anastomosis between thedistal end of the left internal mammary artery and a coronary arterytargeted for bypass; closing the controlled opening in the aorta andpericardium; and withdrawing the at least one catheter from the aorta.13. The method of claim 10, wherein at least one of the steps isconducted using computed tomography (CT) guidance.
 14. The method ofclaim 10, wherein the at least one catheter comprises a Hansen Device.15. A device for performing a medical procedure on a patient's heartcomprising: at least one catheter for the percutaneous delivery of ahemostatic connector into an aorta of a heart; a flange for forming ahemostatic connection between the at least one catheter and an innerwall of the aorta to form a catheter-aortic interface, wherein thehemostatic connection substantially prevents blood from flowing throughthe catheter-aortic interface; and a means for forming an aperturethrough the aorta into a pericardium, wherein the aperture is bounded bythe hemostatic connection, thereby forming a controlled opening toaccess a thoracic region of the patient's chest through the at least onecatheter.
 16. The device of claim 15, further comprising a non-occludingballoon member for releasably forming the hemostatic connection at thecatheter-aortic interface, wherein inflation of the non-occludingballoon member does not substantially interfere with blood flow throughthe aorta.
 17. The device of claim 15, further comprising one or morecounter-supports to the flange for releasably forming the hemostaticconnection at the catheter-aortic interface, the one or morecounter-supports protruding radially from the catheter opposite thecatheter-aortic interface.